Image guided surgery (IGS) procedures (sometimes referred to as “computer assisted surgery”) were first developed for use in neurosurgery and have now been adapted for use in certain ENT surgeries, including sinus surgeries. See, Kingdom T. T., Orlandi R. R., Image-Guided Surgery of the Sinuses: Current Technology and Applications, Otolaryngol. Clin. North Am. 37(2):381-400 (April 2004). Generally speaking, in a typical IGS procedure, a digital tomographic scan (e.g., a CT or MRI scan) of the operative field (e.g., the nasal cavities and paranasal sinuses) is obtained prior to surgery. A specially programmed computer is then used to convert the digital tomographic scan data into a digital map. During surgery, sensors or markers mounted on the surgical instruments send data to the computer indicating the position of each surgical instrument. The computer correlates the data received from the instrument-mounted sensors with the digital map that was created from the preoperative tomographic scan. One or more image(s) is/are then displayed on a monitor showing the tomographic scan along with an indicator (e.g., cross hairs or an illuminated dot) of the real time position of the surgical instrument. In this manner, the surgeon is able to view the precise position of each sensor-equipped instrument relative to the surrounding anatomical structures shown on the tomographic scan.
The currently available IGS systems fall into two main categories, namely, optical systems and electromagnetic systems. In electromagnetic IGS systems, electromagnetic sensors (e.g., electromagnetic coils) are attached to the surgical instrument and the computer determines the position of the instrument within the body on the basis of signals received from those electromagnetic sensors. Examples of commercially available electromagnetic IGS systems that have been used in ENT and sinus surgery include the ENTrak Plus™ and InstaTrak ENT™ systems available from GE Medical Systems, Salt Lake City, Utah. Other examples of electromagnetic image guidance systems that may be modified for use in accordance with the present invention include but are not limited to those available from Surgical Navigation Technologies, Inc., Louiville, Colo., Biosense-Webster, Inc., Diamond Bar, Calif. and Calypso Medical Technologies, Inc., Seattle, Wash.
The electromagnetic sensors must be attached to the instrument in a manner that maintains the sensors in specific, fixed spatial relationships to the portion of the instrument that is to be tracked within the body. In some cases, the sensor(s) may be built into the instruments at the time of manufacture. In other instances, it may be desirable to attach one or more electromagnetic sensors (or a module containing the sensor(s)) to an instrument immediately prior to or during use of that instrument in a therapeutic procedure.
In the ENT field, one particular area in which it is desirable to attach electromagnetic sensors to instruments is in the performance of procedures where rigid and/or flexible catheters and other devices are inserted through the nose and used to perform sinus surgery or other sinus treatment procedures. One such procedure is balloon dilation of sinus cavity ostia. In such procedure, a guide catheter having a substantially fixed shape is inserted through the nose and advanced to a position where the distal end of the guide catheter is adjacent to the ostium of a paranasal sinus. A guidewire is then advanced through the guide catheter (e.g., Relieva™ Guide Catheter, Acclarent, Inc., Menlo Park, Calif.) and into the paranasal sinus. Thereafter, a balloon catheter (e.g., Relieva™ Balloon Catheter, Acclarent, Inc., Menlo Park, Calif.) is advanced over the guidewire and is used to dilate the ostium of the paranasal sinus, thereby improving drainage from and/or ventilation of that paranasal sinus. Since the guide catheter has a substantially fixed shape, electromagnetic sensors may be mounted on the proximal portion of the guide catheter in positions that bear known spatial relation to the distal end of the guide catheter. In this manner, those proximally mounted sensors may be used in conjunction with an electromagnetic IGS system to track the position of the distal end of the guide catheter within the subject's body. However, to accomplish this, the sensors must be firmly mounted and maintained in specific positions on the proximal end of the guide catheter.
Thus, there remains a need in the art for the development of new adapter devices that may be used to securely attach electromagnetic sensors (or receiver modules that contain the sensor(s)) to guide catheters and/or other devices useable in the performance of balloon dilation procedures as well as other instruments used in ENT and other surgical procedures.